The present invention relates to an earth working machine, such as a road milling machine, recycler, stabilizer, or surface miner, encompassing a machine body having a machine frame and a drive configuration rotationally drivable relative to the machine frame around a drive axis that defines an axial direction, to which configuration a working apparatus embodied for earth working is releasably connected in torque-transferring fashion, in an operating position operational for earth working, for rotation together around the drive axis, such that when the connection is released, the working apparatus is removable from the operating position in an axial direction relative to the drive configuration for deinstallation from the drive configuration and, for installation on the drive configuration, is conveyable into the operating position in an axial direction relative to the drive configuration.
DE 10 2012 008 252 A1 of the species discloses an earth milling machine having a milling drum, rotatable around the drive axis of a drive configuration, constituting the working apparatus, the milling drum being rotatable around the drive axis only when the milling drum is in its operating position relative to the drive configuration and is connected thereto for rotation together around the drive axis.
The drive configuration of the known earth milling machine is located radially inside the milling drum when viewed with the known earth milling machine in the operational state. The milling drum is braced against the drive configuration at two bearing points located with an axial spacing between them, the bearing point located closer to the drive side forming, by means of a spur tooth set, a positively engaging coupling for torque transfer between the drive configuration and milling drum. On the drive side of the earth milling machine, a drive torque is transferred from the drive motor to the drive configuration. DE 10 2012 008 252 A1 discloses, without further detail, that the positively engaging coupling itself, i.e. the spur-toothed components of the machine body of the earth milling machine on the one hand and of the milling drum on the other hand which mesh with one another in the operational state, are intended to comprise a “pressure impingement device” for fluid pressure impingement upon the positively engaging coupling in order to separate the coupling halves. Separation of the positively engaging coupling halves is preferably to be accomplished pneumatically.
The earth milling machine known from DE 10 2012 008 252 A1 can furthermore comprise a cylinder/piston unit so as to push the milling drum, with this unit, out of the positive coupling engagement toward a non-locating bearing of the milling drum. The non-locating bearing is constituted in the region of the bearing point located farther from the drive side.
Beyond simply reciting the means to be used, however, DE 10 2012 008 252 A1 provides no indications at all as to how the pressure impingement device should be configured, where it and/or the piston/cylinder unit might be located, and how they are to be brought into force-transferring engagement with one or both positively engaging coupling halves.
U.S. Pat. No. 4,704,045 A discloses an earth working machine, likewise in the form of an earth milling machine, whose milling drum constituting a working apparatus is axially clampable in torque-transferring fashion between two drive plates. The drive plates at the two axial end regions of the milling drum are each mounted on a side frame, each side frame of which is axially displaceable by means of hydraulic piston/cylinder units relative to a stationary machine frame of the earth milling machine known from U.S. Pat. No. 4,704,045 A. With the side frames axially displaceable in this fashion, the working engagement point at which the milling drum removes material from the ground can be displaced along the machine width. In addition, the milling drum can be unclamped from, and clamped into, its receptacle by displacing the side frames relative to one another.
DE 40 37 448 A1 discloses a road milling machine in which a milling drum is axially clamped in between a locating bearing located closer to the drive side of the road milling machine and a non-locating bearing arranged on a movable side plate of the machine body on the idle side, located oppositely from the drive side, of the road milling machine. The side plate carrying the non-locating bearing is connected to the machine frame, at a point at a distance from the non-locating bearing, by means of a hydraulic positioning cylinder. The non-locating bearing can be extended out of the milling drum, and pushed into the milling drum, by actuation of the positioning cylinder. Using a corresponding installation sequence it is even possible to ensure that firstly the milling drum, together with the non-locating bearing, is pulled off the locating bearing by actuation of the positioning cylinder, and only then, after release of a connection between the non-locating bearing and milling drum, can the non-locating bearing be pulled off the milling drum by further actuation of the positioning cylinder.
In the case of the positioning cylinder arranged remotely from the non-locating bearing, large installation moments unavoidably act at least on the bearing subassemblies involved during both deinstallation and installation of the milling drum, since a considerable load arm exists between the hydraulic positioning cylinder and the bearing components to be displaced by it.
The solution known from U.S. Pat. No. 4,704,045 A has the disadvantage that the hydraulic positioning cylinders that move the side frames must exert an axial force on the milling drum during the entire operation of the known earth milling machine in order to hold the drum in an axially clamped state. The considerable working reaction forces that occur at the earth working engagement point thus feed back into the hydraulic positioning cylinders. In addition, considerable moments occur here as well upon force transfer between the hydraulic positioning cylinders, arranged at a distance from the drive axis, and the milling drum bearing system.